Furnace



july 29, w21@ 1,502,886

W. M. SHALLCROSS FURNACE 'Filed sep.. 15. 192.1 1 3 sheetssheet :e

foon. 90:

ATTORNEY.

Patented july 29, HQE@ `i site atea 'WILMER IVI. SHALLCB'OSS, 0F MILWAUKEE, WISCONSIN, ASSIGNOR TO SHALSS v CONTROL SYSTEMS CO., OF

CONSIN.

MILWAUKEE, WISCONSIN, .A CORPORATION F WIS- FURNACE'.

Application led September 15, 1921.l Serial No. 500,896.

waukee'and State of Wisconsin, have. in-

vented new and useful Improvements in Furnaces, of which 'the followin is a d escription, reference'being had to t e accompanying drawings, which are a part of this specification.

This invention relates to certain new and -useful improvements in furnaces and refers more articularly to a regulator therefor.

In urnaces, more particularly that typ e employed -for generating steam it is highly desirable that conditions be so re ulated'that each generator unit carries its s are of the load `under various conditions; that maximum' fuel economy'be obtained at all times, and that the `boiler maintenance cost be maintained low.

It is, therefore, primarily an object of this invention to provide means whereby the desired regulation of the furnace is obtained.

It is more specifically an object of this in`l vention to provide means for simultaneously actuating the flue damper and fuel feed of a furnace when the draft within the fire box exceeds a predetermined degree to automaticall reduce the iiue opening and .decrease t e volume of fuel fed the furnace, and, upon the draftfalling below a -predetermined degree, to increase the Hue opening and volume of fuel fed the furnace.

isanother object of this invention to provide means connected with the steam head or outlet of. a steam generator whereby the pressure therein will be maintained substantially constant.

A further object of this invention is to ,provide means for coordinating the flue damper,- furnace fuel supply means, and forced draft means, whereby the furnace condition will be maintained as near as possible to the desired efficient point in order that each unit may carry its share of the l load and that maximum fuel economy may be obtained and boiler maintenance cost kept `at a low figure.

still further object of this invention is to provide electrically operated means connected with the flue damper, fuel supply and forced draft means for maintaining the condition ofthe furnace at a substantially constant point under all load conditions.

i With the above and other objects in view which will appear as the description proceeds, my invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the herein disclosed invention may be made as come within the scope of the claims.

In the accompanying drawings, I have illustrated one complete example of the physical embodiment of my invention con- .structed according to the best mode I have so far; devised for the practical application of the principlesthereof, and inwhich: 1

kFigure 1 1s a view part in section and part .in elevation taken through a steam genera- I employ for controlling the regulation -of the flue damper and fuel feed means upon a change in the draft condition; v Figure 3 is a view part vin section and part in elevation illustrating one of the units employed for regulatin the damper line; fuel supply means and orced draft means; Figure 4 is an enrd view thereof with the motor removed, illustrating in dotted lines the'limit switches which I employ;

in section and part in elevation illustrating the means connected with the. steam head or outlet for controlling the forced draft .'naces, it is highly desirable that each unit be regulated to 'bear its proportionate share of the load under all conditions, be run so that maximum fuel economy will be obtained at all times and that the furnace main- Figure 5 is an enlarged detailed view part tenance cost be kept at a minimum amount.

To obtain these desired objects, it is necessaryd that all the elements, essential to the eflicient operation of the furnace, be coordiplyy of fuel to the re box must be increased proportionately with the flue damper openingin order that the fire may be properly maintained, or, 'in the event the draft should increase beyond the desired degree, the damper must be movedtoward closed position and the fuel supply proportionately decreased. The forced draft means must also 4be regulated so that, upon a fall of the steam pressure from a predetermined degree, the same must be increased, or upon a rise in y. the steam pressure beyond predetermined degree be decreased.

A Many attempts have been made to regulate' .a furnace to obtain -the desired efficiency of operation, all of which havejfailed in some feature, and, in the invention illustrated by the accompanying-drawings, I obtained the ,desired maximum efficiency in boiler operation by electrically connecting the damper iiue, fuel. supply means and forced draft means with suitable regulators that are sensitive to changes in the boiler condition and,

' throu h means of the circuits hereinafter de'scri ed, regulate the damper flue, lfuel means and forced draft means as the condition of the furnace requires.

In the accompanying drawings, the numeral 7 designates a steam generating unit or furnace,`which may be of any design or construction, having a 'fire box 8 provided with suitable fuel supply means`illustrated' in the present instance as an automat-ic stoker having an operating engine 9, a forced draft means 9 communicating with the ash pit ,10` beneath the lire box by a duct 11', a

chimney or fiue 12 for carrying off thev burnt lor exhausted gases and a steam header -13 having an outlet 14 for carrying the steam j to the-various desired points of consumption.

Connected at some point with the interior vof the fire box 8 is a pipe or duct 15 which communicates with the interior of a pontoon I switch 16 consisting of a fluid container 17 havinga central pan 18 therein forming an' annular trough or channel 19 within the container for receiving a suitable fluid. The

pipe or duct 15 terminates in a valve 20, one

end of which` communicates `with the inner chamber of the pontoon switch centrally of the pan 18, the handle 21 ofthe valve ex `tending to an exterior point whereby the sensitiveness of the .regulation of the flue damper opening and thev fuel 'feed by the draft within the iire box 8`may be con- Vtrolled. Secured within the container 17 -is Ian inverted pan orgas'bell 22,' the rim of which projects into the iuid v.within the channel 19 and centrally carried by the top of the gas4 bell in alignment with an aperbracket member 25 to which is secured one end of a spring 26 having its upper end secured to one end 27 of a bell crank lever The spring 26 is confined within a tube or cylinder -29 which covers opening 23 and into which projects bell crank lever end 27 through an elongated opening 30 in the wall thereof. Also confined-within tube 29 is a second spring 31 having its lower end se'- cured to cud 27 of the bell crank levery and its upper endsecured to an adjustable screw 32 carried bythe cap 33 of the tube.

The lever 28 is pivotally secured at its apex between a bracket. member- 34 carried by aswitch casing 35'wliich completely conceals said lever andthe lswitch construction now about to be described- The end 36 of lever 28 has two contacts 37 and 38 secured to opposite sides thereof adapted forelectrical connection with contacts 39 and 40 respectively, carried by two spring contact carrying members 41 and 42 secured attheir lower ends as at 43 tothe casing 35. Secured to the sides of the members 41 and 42 opposite thel contacts 39 and 40 respectivelyy are contacts 44 and 45 respectively, adapted ture 23 in the top 24 of container 17 is a to be electrically connected with contacts 46 and 47 respectively, carried by thev casing 35. The upper ends 'of levers .41 and 42 carry contacts 48 and'49 respecti'. fly, arranged for electrical connection with stationary contacts 50 and 51 respectively Positioned within the flu 12 is a damper or other' regulating valve ieans 52 which may be of any desired construction, but in the present instance is illustrated asa plate carried by a rotatably mounted shaft 53 one,

be connected with a suitable control means by .a rod 55'. In this invention the rod 55 is connected with a suitable electric reguiio iating device illustrated in Figures 1, 3 and 4 having a vcrank arm 56 carried by a shaft 57 driven from a motor'58. The drive shaftv 59 of the motor extends into a gear reducftionhousing 69 and has a worin 61 mount. Aed thereon which meshes with a worm wheel 62 carried by ashaft '63 which also carried [limit switches 66 and ,67 are provided which open the electrical'circuit, to be later described, whenvthe arm 56 re-aches either of its limitsof movement.

The control member 68 of the furnace fuel supply means has a crank arm 69 carried by its operating shaft which is 'also col iectedby a rod 7,0 with a device similar iso to that illustrated in Figure 3 and therefore further description thereof is deemed unnecessary. With 'this construction p it will be readily obvious that a rotation of the crank 56 of the device connected with the fuel supply means in one direction will in crease the volume of fuel supplied the furnace and a rotation thereofin a reverse direction .will decrease theA volume of fuel supplied the furnace. The motors 58 connected with the fuel supply means and the damper 52 are preferably simultaneously operated to decrease the volume of fuel supplied the furnaceand the degree of opent ing of the damper 52 upon the increase in the through a switch mechanism 74 with a posi' tive line 75, the other end of the field 71 having a conductor 76leading therefrom to the limit switches 66 and 67, limit switch 66 being connected with a conductor 77 which connects contact 4 8 with terminal 78 of a hand switch 79. Limit switch- 67 vis yconnected with contact 49 by a conductor and with a contact 81 of a hand switch 821by a conductor 83.* Contact 50 is connected with one end` of a resistance 84 by a conductor v85 and contact-5 51 is connected with one end of a resistance 86'by a conductor 87, the other end of resistance 84 and 86 being-connected with a common conductor 88, in connection with a negative service line 89 through 'switch 74, by conductors 90 and 91 respectively. Con- .tacts 44, 45, 46 and 47 are connected with the conductors 85, 87, 90 and 91 respectively, whereby electrical connection of the contacts 44 and 46 will cutout resistance 84, and electrical connection of contacts 45 and 47 will cut out resistance 86, for the n reasons hereinafter set forth.

Contacts 39 and 40 are connected with the conductor 87 by a common conductor 92 and contacts 37 and 38 are connected'by a common conductor 93 withl a contact 94 of switch 79, the blade 95 of said switch which engages contact 94 when in its upper position being .connected by a conductor 96 with a contact 97 of switch 82. The blade 98 of switch 82 which engages contact 97 when in its upper position 1s connected with the blade 99 of switch 79 through the armaturey 72, the other upper contact 100 ofV Lacasse! contacts 81 and b kdraft control means.

switcli 79 ,being connected with the other blade 101 of switch 82 by a conductor 102, u

and the upper contact 103 of switch 82 being connected with conductor 85 by aconductorl04. The lower contacts 105 and 106 of switches 79 and .82, respectively, are connected with the conductor 88 by a common conductor 107 and leading from contact 78 to blade 98 is a line 108 having therein a pilot li ht 109, and connecting ade99 is a line 110 in which is positioned a pilot light 111.

Shunting across conductors 76 and 88 is a line 112 having therein a shunt field 113 which 'permits use of any type of motor,

shunt type. lVhen a series motor is employed, 'only field 71 is used and the shunt 113 is eliminated, when a shunt motor is used field'71 is eliminated and when a compound motor is used both Ythe field 71 and the shunt 1.13 will be employed as will be i. e. motors of the series, compound or l readily obvious -to those skilled in the art A to which this invention appertains.

Positioned within the forced draft duct 11 is a'control member 114, vto the operating arm 11-5 of which a device similar to A that disclosed in Figure 3 is connected by a rod 116.- The motor of the forced draft controlling unit is controlled by a switch similar to that disclosed in Fi ure-2 and actuated f by meansconnected wit the steam drum 13 or outlet 14 and sensitive to increase or decrease in the steam pressure to produce a corresponding adjustment of the forced Secured within a casing 117 is a stationary cylinder 118 in .which is eciprocally mounted a piston 119 having the upper-most end of its piston rod secured in the up er end 120 of a yoke member 121 reciprocaly mounted about the cylinder, the yoke bein connected with the end 27 of switch bel crank lever 28 by a link 122 preferably pivotallycarried by a part 123 carried 'by the extreme upper end Iof the piston rod and pivotally 'connected with the lever end 27 as at crank lever-28 1s11`v1orrr1ally` urged toits inter-4 mediate or central Aposition by a spring125' lio 124. ln this form of my invention the bell secured as at 126. to thecansing 117 and to an arm 127 carried by thebell-crank lever.

The lower closed endof the cylinder 118 lis connected by a pipe `128 .with either the outlet 14 or^the steam head 13 whereby a de- 120 'crease in the generator vsteam pressure'will l permit an inward movement ofthe iston in th'e cylinderand an-increase int e steam pressure will cause an outward movement of the piston.r` VThe device isadjuste'd sothat lever 28wil1 beheld in its intermediate po- Ysitionat a predetermined steam pressure by weights 129 carried by a Tod 130 suspended from the lower end of yoke y121.

From the foregoing ldescription taken in connection with the accompanying drawingsit will be readily seen that the operation of a furnace equipped with my invention will be substantially as follows :H-

`Assuming that the condition of the furnace is at the desired point i. e. the steam pressure is at its predetermined degree and the draft through the fire box 8 is of the degree desired and the steam pressure then falls below the 4set point. As the steam pressure decreases, piston 119 moves inwardly swinging switch arm 36 to the left, Figures 2 and 5, electrically connecting contacts 87 andA 39. At this point the current flows through eld 71, divides at limit switches 66 and 67 and passes through resistance 84 and 86 to conductor 88 and out through line 89 andthe motor 58 for actuating the forced draft control means remains inoperative. A further fall of the steam pressure causes a continued inward movement of the piston until contacts 48 Aand 50 arerbrolren, thus causing the current to flow through field 71,

conductor 76, limit switch 67, contacts 49 and 51, where the current is again divided and part of it flowing through resistance 86 and out through line 89 and conductor 88 and the.

rest through conductor 92, contacts 39 and 37, conductor 93, switch blade 95, conductor 96, switch blade 98, armature 72, switch blade 99, conductor 102, switch blade 101, conductor 104, conductor 85, resistance 84, conductor 90 and thenl through conductor 88 to line 89. With the parts in this position the motor 58 controlling the forced draft means operates at lslow speed'.

With the forced draft actuating motor operating at slow speed pilot light 111 w1ll burn at half brilliancy by reason of the curl creases, the piston 119 is urged outwardly to return the switch parts to normal position and should the pressure exceed the set degree, contacts 38 and 40 will be closed when the flow of current is substantially the same as that first described. A continued rise in the steam pressure causes contacts 51 and 49 to be disconnected when the division of the current is then through limit switch 66, contacts 48 and 50, conductor 85, conductor 104, switch blade 101, conductor 102, switch` blade 99, armature 72, switch blade 98, conductor 96, switch blade 95, conductor 93, .contacts 38 and 40, conductor 92, conductor 87,

resistance 86, conductor 91, conductor 88, and out through line 89, the motor 1s then running at slow speed to close force draft control member 114. The other division of the current with parts. in the condition just described is through limit switch 66, conductor 77, conductor 108 and consequently pilot light 109, switch blade 98, conductor 96, switch blade 95,`cnductor 93, contacts 38 and 40, conductor 92, conductor 87, resistance 86, conductor 91, conductor 88 and out through line 89, the pilot light 109 thus burnin@ at half brilliancy.

Shou d the steam pressure continue to rise the contacts 45 and 47 will be electrically connected to cut out resistance 86 and drive thel motor 58 at full speed, until the limit switch is actuated, and-also to burn the pilot light 109 at full brilliancy. The ob-,` ject of having conductors 92 and 93 electrically disconnected when the operating switch is in normal position, is to eliminate any possibility of creepage of the motor should the contacts 48 and 50, and 51 and 49 vbecome dirty or one afford more resistance to the flow of current. than the other as -will be readily apparent. With this arrangement of the circuits a powerful dynamic braking eect is also produced as when contacts 48 and 50, and 49 and 51, respectively are connected, the-armature is short circuited and consequently immediately stopped.

l/Vhen the draft within the lire box 8 falls 'below the set degree, the'gas bell 22 is permitted an upward movement to permit contacting of contacts 38 and 40 of the switch mechanism connected therewith, or in the event the gas suction increases beyond the desired degree, the movement thereof is reversed, and as the operation of the switch mechanism and the various electrical circuits, described in connection'with the forced draft regulating device, is identical with the damper regulator and feed control, further description is deemed unnecessary. l

For the purpose of disconnecting the automatic control feature, hand switches 79 and 82 are employed as will be readily appre-l ciated. The hand switches 79 and 82 are primarily for operating the regulating devices independent of the pontoon switch 16 vand the steamcontrolled device.

mal, and means within the circuit whereby i,

a strong dynamic braking force is applied to said motor upon the furnace condition` returning to normal.

2. ln a furnace, regulatin means there for including an electrical evice, an elecizo i for including an electrical i,soa,ese

tric circuit including said device, means Within said circuit for automatically actuating said `device upon the furnace condition changing from normal, and means Within the circuit for permitting manual manipulation of said device.

3. In :t furnace, regulatin means thereevice, an electrical circuit including said device, means within said circuit for automatically actuating said device upon a change in the furnace condition from a predetermined condition, and means permitting the actuation of said device independently of said automatic means.

d. In a furnace having a fire chamber, means for feeding fuel to the lire chamber, forced draft means connectible with the lire chamber and steam outlet, of an electric motor connected with said fuel feeding means to control the same, an electric motor connected with said forced draft means to control the same, a. circuit making and breaking device, circuits including said circuit making and breaking device and said fuel feeding control motor and forced draft means controlling motor, and means actuated by the pressure at said steam outlet for operating said circuit making and breaking device, whereby the adjustment of said fuel feeding means and said forced draft means is coordinated with the outlet.

pressure at said steam 5.7In a furnace having a ire chamber,

chamber, a Ihre damper and a steam outlet, of an electric motor connected with said fuel feeding means to control the same, an electric motor connected with said forced draft means to control the same, an electric `motor connected with said flue damper to control the saine, a circuit making and breaking device, circuits including said circuit making and breaking device and said fuel feeding 'control motor and forced. -draft means control motor, means actuated by the pressure at said circuit making and breaking device, whereby the operation of said fuel feeding means and said forced draft means is coordinated With the pressure at said steam outlet, a second circuit making and breaking device, a circuit including said circuit making and breaking device and said flue damper control motor, and means actuated by the pressure Within said fire chamber for operating said second circuit making and breaking device, whereby the adjustment of said Hue damper is coordinated with the pressure in the fire chamber and consequently with the operation of Said fuel feeding means and said forced draft means.

In testimony whereof, I aiiix my signature.

WILMER M. sHaLLcRoss. 

